What is crossfeed in the 787 fuel system used for?

• A. To balance fuel between tanks and optimize weight and balance.
• B. To feed hydraulic fluid between systems.
• C. To vent fuel from tanks.
• D. To cool the engines with fuel.

Answer: (A)

Crossfeed in the 787 fuel system is the capability to move fuel between tanks so you can even out the fuel distribution and keep the aircraft’s weight and balance within safe limits as fuel is burned and payload changes. By transferring fuel from a fuller tank to a lighter one, the center of gravity stays within approved envelopes, which helps maintain stability and performance. It also provides a reliable fuel source to an engine from either side if needed, aiding engine-out operations or pump issues. This function is specific to fuel management and isn’t used for hydraulic fluid transfer, venting, or cooling engines with fuel.